New build 454 and the wife hates the exhaust smell

[txaggie]

Howdy all!

I recently rebuilt an 85 suburban 454 and stripped the factory exhaust off for a hooker black heart 2.5” x pipe dual system. Well, my lovely wife hates the exhaust smell and I was curious if some high flow cats might cut down on it?

Let me know if anyone has any recommendations! 454 bored .030 over, Holley sniper, long tubes, etc.

 

[Tonimus]

How long have you been running the sniper? Takes a little bit for Holley systems to lean out since fatter is generally safer. You could throw a smaller tune at it as well. Tell the unit it's a 396 or something.

 

[txaggie]

How long have you been running the sniper? Takes a little bit for Holley systems to lean out since fatter is generally safer. You could throw a smaller tune at it as well. Tell the unit it's a 396 or something.

A few weeks. I was just curious on how much (if any) a high flow cat might cut down on the stink?

 

[DoubleDingo]

It will, and there are threads on the subject if you do some searching

 

[txaggie]

It will, and there are threads on the subject if you do some searching

Thanks. Do you have a recommendation on any brands?

 

[DoubleDingo]

Thanks. Do you have a recommendation on any brands?

I don't, but there is plenty of info in the threads. Brand used, placement downstream, etc

 

[3 Ton]

Let me know if anyone has any recommendations!

Dump the Chinese made Holley crap, some of them work, some do not. Why take the chance.
i had one client that both Mom, Dad, and he installed Holley crap on all 3 trucks. They had to go back to a carb because one would not work right.

BTW I did carburation parts before I retired. Holley went out of business the same time Carter and Rochester were forced out of business. Everything NEW is from China, and its all junk. Any of these names on new carbs are Chinese made. 100%

Where do your tail pipes end up? Blowing exhaust back into he cabin is usually on how far back they go.
You have not stated if its leaking form the pipes OR coming form outside in.

 

[txaggie]

Dump the Chinese made Holley crap, some of them work, some do not. Why take the chance.
i had one client that both Mom, Dad, and he installed Holley crap on all 3 trucks. They had to go back to a carb because one would not work right.

BTW I did carburation parts before I retired. Holley went out of business the same time Carter and Rochester were forced out of business. Everything NEW is from China, and its all junk. Any of these names on new carbs are Chinese made. 100%

Where do your tail pipes end up? Blowing exhaust back into he cabin is usually on how far back they go.
You have not stated if its leaking form the pipes OR coming form outside in.

Sniper II and it runs perfect thus far. Exhaust exits behind both rear wheels.
Exhaust smell does come in the cabin especially when sitting at a light for a bit. On the highway it is good.

 

[Bextreme04]

Howdy all!

I recently rebuilt an 85 suburban 454 and stripped the factory exhaust off for a hooker black heart 2.5” x pipe dual system. Well, my lovely wife hates the exhaust smell and I was curious if some high flow cats might cut down on it?

Let me know if anyone has any recommendations! 454 bored .030 over, Holley sniper, long tubes, etc.

The answer is yes, cats will absolutely reduce the smell. I have dual 3" Flowmaster high flow cats on my 2011 Burb and still get a small bit of exhaust smell because they aren't enough for a slightly angry 6.2L. You don't have any need for a high flow cat on your application. Modern federal legal cats are not going to restrict exhaust flow at all and will only be beneficial. I had to use the high flow because the design of the Y-pipe in my application did not have room for regular cats once the long tube headers were put in. A dual exhaust on a squarebody should have plenty of room for regular cats. Do you have headers on it? If so, you can just weld the header flange right on one side of a universal cat. If using regular manifolds you will need to have it worked to get the cats as close to the manifold output flanges as possible.

2 of these are exactly what you need and would even have free shipping. You'd be all-in for less than $200.
https://www.flowmastermufflers.com/...QVSu_YJf5ioXSwX3bXqH3XjtDHGURXY8aAhC4EALw_wcB

 

[txaggie]

The answer is yes, cats will absolutely reduce the smell. I have dual 3" Flowmaster high flow cats on my 2011 Burb and still get a small bit of exhaust smell because they aren't enough for a slightly angry 6.2L. You don't have any need for a high flow cat on your application. Modern federal legal cats are not going to restrict exhaust flow at all and will only be beneficial. I had to use the high flow because the design of the Y-pipe in my application did not have room for regular cats once the long tube headers were put in. A dual exhaust on a squarebody should have plenty of room for regular cats. Do you have headers on it? If so, you can just weld the header flange right on one side of a universal cat. If using regular manifolds you will need to have it worked to get the cats as close to the manifold output flanges as possible.

2 of these are exactly what you need and would even have free shipping. You'd be all-in for less than $200.
https://www.flowmastermufflers.com/...QVSu_YJf5ioXSwX3bXqH3XjtDHGURXY8aAhC4EALw_wcB

Thank you!

 

[Vbb199]

If you know how to extract the tune from the holley, i can help you enlean it a little so its not so stinky

The stock tunes from holley idle at like 13.x afr , which is gonna be a little stinky.
PM me if you'd like to

 

[fast 99]

With cat overly rich mixture will smell like rotten eggs. Depending on how rich it is possible the media could melt down, plug up and/or have a very short life.

Lean mix will usually burn the eyes.

Today with inexpensive 02 gauges available install one for diagnostic purposes. Should get an idea where the emissions are before going the cat rout.

 

[Matt69olds]

Find someone who can tune the system for you. The self tuning will get it close, having it custom tuned will make a world of difference.

Having said that, I’d consider using the matching distributor and using the sniper for timing control also.

Hope you don’t have any issues with your sniper. It’s safe to say holleys quality control leaves much to be desired.